[Ips-dsgr] SWS Daily Report - 26 April 21 issued 2330 UT on 26 Apr 2021

Tue Apr 27 09:30:09 EST 2021

SUBJ: SWS DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/26 APRIL 2021 BY Space Weather Services
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
SUMMARY FOR 26 APRIL AND FORECAST FOR 27 APRIL - 29 APRIL
STATUS INDICATORS SOL:GREEN   MAG:GREEN     ION: GREEN
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1A. SOLAR SUMMARY
Activity 26 Apr:  Low

Flares: none.

Observed 10.7 cm flux/Equivalent Sunspot Number for 26 Apr:  80/20

1B. SOLAR FORECAST
             27 Apr             28 Apr             29 Apr
Activity     Low                Low                Low
Fadeouts     None expected      None expected      None expected
10.7cm/SSN    80/20              78/17              78/17

COMMENT: Solar activity was low on UT day 26 April with multiple 
B-class flares from region 2820 and a C1.3 flare from region 
2816. There are currently five numbered regions on the visible 
disk, ARs 2816, 2818, 2819, 2820, and 2821. There was a large 
filament eruption visible in SDO images near S54W14 at about 
26/1346 UT. Further analysis is required to determine if there 
is a CME associated with this event. No other Earth directed 
CMEs were observed in the available images. Solar activity is 
expected to be low for the next three UT days, 27-29 April, with 
a slight chance of an M-class flare. On UT day 26 April, the 
solar wind speed remained enhanced, varying mostly between 450 
km/s and 530 km/s because of the 22 April CME. The IMF (Bt) peaked 
at 8 nT and the north-south IMF (Bz) range was +5/-7 nT. The 
IMF Bz component sustained a southward orientation during 26/0000-0550 
UT and was mostly negative after 26/2030 UT. The enhanced solar 
wind conditions are expected to start decreasing back to nominal 
levels on UT day 27 April.

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2A. MAGNETIC SUMMARY

Geomagnetic field for Australian Region 26 Apr: Quiet to unsettled 
with isolated active periods

Estimated Indices 26 Apr : A   K           
   Australian Region       4   32211001
      Cocos Island         3   31201000
      Darwin               5   32311001
      Townsville           7   42311001
      Learmonth            5   42211000
      Alice Springs        4   32201000
      Gingin               4   32202000
      Canberra             4   32202001
      Hobart               6   33212001    

Estimated Antarctic Regional K Indices 26 Apr :
      Macquarie Island    13   44423001
      Casey                9   43321101
      Mawson              43   77422104

Observed Regional daily pc3 Indices 26 Apr : 
      Darwin               2   (Quiet)
      Townsville           0   (Quiet)
      Learmonth            0   (Quiet)
      Alice Springs        3   (Quiet)
      Gingin               0   (Quiet)
      Canberra             0   (Quiet)
      Melbourne           NA

Pc3 pulsations are high frequency (10-45 second period) variations 
of the Earths magnetic field. Daily pc3-indices are the daily sum 
of 20 minute pc3-indices for that station and have been shown to be
well correlated with rejection of high resolution aeromagnetic
survey flight-line data. 

NOTE: Indices may have been generated from data obtained in 
cooperation with the following organisations: Geoscience Australia, 
University of Newcastle Space Physics Group, Australian Government 
Antarctic Division and International Center for Space Weather 
Science and Education, Japan.

Estimated AFr/Ap Indices 26 Apr : A 
           Fredericksburg        14
           Planetary             16                         

Observed AFr/Ap Indices 25 Apr :  A   K
           Fredericksburg        16
           Planetary             19   5434 3232     

2B. MAGNETIC FORECAST 
Date      Ap    Conditions
27 Apr    10    Quiet to Unsettled
28 Apr     8    Quiet to Unsettled
29 Apr     7    Quiet

COMMENT: Geomagnetic conditions in the Australian region were 
at quiet to unsettled levels with isolated active periods on 
UT day 26 April. Quiet to storm levels were observed in the Antarctic 
region. Mostly quiet to unsettled conditions are expected on 
UT day 27 April due to waning CME effects; however, isolated 
active periods are possible. Then mostly quiet to unsettled conditions 
are expected on UT days 28-29 April.

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3A. GLOBAL HF PROPAGATION SUMMARY
	            Latitude Band
Date        Low            Middle         High 
26 Apr      Normal         Normal         Normal-fair    

PCA Event : No event.

3B. GLOBAL HF PROPAGATION FORECAST
	            Latitude Band
Date        Low            Middle         High 
27 Apr      Normal         Normal         Normal-fair
28 Apr      Normal         Normal         Normal-fair
29 Apr      Normal         Normal         Normal-fair

COMMENT: Mostly normal HF propagation conditions are expected 
on UT days 27-29 April.

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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY

Date   T index
26 Apr    20

Observed Australian Regional MUFs
   Cocos Island Region:
      No data available.
   Niue Island Region:
      No data available during local day.
      Near predicted monthly values during local night.
   Northern Australian Region:
      Near predicted monthly values.
   Southern Australian Region:
      Near predicted monthly values.
   Antarctic Region (Casey/Scott Base/Davis/Mawson):
      Near predicted monthly values over the UT day.

Monthly T index:
Month  T index
Mar      9
Apr      19
May      23

4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date   T index  MUFs
27 Apr    20    Near predicted monthly values
28 Apr    15    Near predicted monthly values
29 Apr    15    Near predicted monthly values

COMMENT: SWS HF Communications Warning 12 was issued on 24 April 
and is current for 25-27 Apr. MUFs in the Australian region on 
UT day 26 April were mostly near predicted monthly values. MUFs 
are expected to be mostly near predicted monthly values on UT 
days 27-29 April.

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5. SPACE ENVIRONMENT SUMMARY

GOES satellite data for 25 Apr
       Daily Proton Fluence >1 MeV:   7.1E+04
       Daily Proton Fluence >10 MeV:  4.3E+04
       Daily Electron Fluence >2 MeV: 1.80E+07   (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 3%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
       X-ray background: A6.6

DSCOVR Satellite Solar Wind Day Averaged Data for 25 Apr
Speed: 475 km/sec  Density:    9.4 p/cc  Temp:   250000 K  Bz:  -1 nT

(Courtesy Space Weather Prediction Center, Boulder USA)
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Space Weather Services              email: asfc at bom.gov.au
Bureau of Meteorology
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Haymarket NSW 1240  AUSTRALIA       FTP: ftp://ftp-out.sws.bom.gov.au
tel: +61 2 9213 8010                fax: +61 2 9213 8060 

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